SALINA -- The type of relationship a woman has with her ex-partner is a factor in how the couple shares custody of children, according to a Kansas State University expert on postdivorce and co-parenting relationships.

In a study of divorced or separated mothers sharing physical custody of their children with their former partners, Mindy Markham, assistant professor of family studies and human services on the university's Salina campus, identified three patterns of co-parenting -- continuously contentious, always amicable and bad to better -- as well as negative and positive factors that influenced the mothers' co-parenting relationships.

Markham's study involved 20 predominately white, well-educated women between the ages of 26 to 49 who were divorced or separated from the father of their children. The mothers, from two Midwestern states, shared with their former partners legal and physical custody of the children, who ranged in age from 21 months to 12 years. At the time of the study, the couples had been separated or divorced from six months to 12 years.

"The findings of this study suggest that shared physical custody relationships are dynamic and can vary greatly," Markham said.

Today it is common for both ex-spouses to share legal and physical custody of children after divorcing. But Markham said few studies have looked at the process of co-parenting, so little is known about how divorced parents negotiate the co-parenting process.

In Markham's study, nine mothers had continuously contentious co-parenting relationships with their ex-partners from the time of separation to the present. The negative factors that contributed to this rocky relationship included the mother's perception of her ex's parenting abilities; financial concerns, including the ex not having a job or not paying child support; control or abuse by the ex-partner; and the inability of the ex to separate marital -- or personal -- issues from the co-parenting relationship.

"All mothers in this type of co-parenting relationship reported differences in parenting styles and were concerned with how the ex was raising the children," Markham said. "Parenting practices that concerned the mothers varied greatly and included putting children in harmful situations, not bathing the children, not disciplining them and having no rules or routines. It was especially difficult for these mothers to share custody with ex-partners who were uninvolved during the marriage. They didn't believe their exes were responsible parents."

Markham said eight of the women in the continuously contentious relationships didn't want to share custody of the children with their ex-partner, but most were told by lawyers or the court that they would have to do so.

Four mothers in the study had amicable co-parenting relationships, where they reported always getting along with their ex-partners from separation to the present. The positive factors that affected these relationships were that the mothers believed their ex-partners were responsible parents, money wasn't a source of conflict and the mothers chose to share physical custody.

Seven of the mothers in the study had bad-to-better co-parenting relationships, where co-parenting was contentious at the time of separation, but greatly improved over time. At the time of the study, these women's relationships were similar to those of women with always amicable relationships. These mothers wanted to share physical custody, thought the father was a responsible parent and most said money was not a source of conflict.

But all mothers in bad-to-better relationships said they were unable to co-parent amicably with their ex-partner in the beginning because personal issues were not kept separate from parenting responsibility.

"Although ex-partners with bad-to-better relationships originally allowed their feelings about one another to negatively affect their co-parenting, at some point they realized this was not beneficial and made a conscious effort to change the relationship for the sake of their children," Markham said.

Communication with the ex-partner also played a role in the co-parenting relationship. In the always amicable and bad-to-better relationships, mothers were able to communicate well with ex-partners. These mothers said this made discussing differences in parenting styles easier.

But for women in continuously contentious relationships, lack of communication was a big issue, Markham said. These mothers limited direct in-person or phone communication with their ex, preferring alternative methods like texting or email. They also avoided seeing their ex in person when it came time to exchange children by having them picked up at day care or school.

Markham said she was surprised by the level of animosity that accompanies shared custody, at least from some mothers' perceptions.

"Nearly half of the mothers in this study continue to have conflicted relationships with their ex-partners, and conversations with these women negate the notion that shared physical custody ensures cooperative, less conflicted relationships," she said. "This study can be important for helping professionals recognize that shared physical custody is not a panacea for postdivorce problems -- and that in some cases it exacerbates them."

Markham initiated the study as part of her dissertation work at the University of Missouri. A paper she co-wrote based on a secondary analysis of her dissertation and another grounded theory conducted at Missouri was published recently in the journal Family Relations. A second paper, co-written with her major professor, Marilyn Coleman, Curators professor and director of graduate studies for human develop and family studies at Missouri, is pending publication.

Markham is currently working on a Family Process Institute-supported study about how men and women who share physical custody of their children communicate.